Hurricane Ernesto Discussion Number  16
NWS National Hurricane Center Miami FL       AL052024
1100 AM AST Thu Aug 15 2024

Dry air appears to be disrupting Ernesto's attempts to become more
organized.  Recent microwave satellite imagery has shown a large dry
slot wrapping into the center of the hurricane.  An Air Force
Reserve reconnaissance aircraft currently investigating Ernesto has
found peak flight-level winds of 87 kt and an expanded surface wind
field. Normally, this elevated wind would reduce to a surface wind
speed of 75-80 kt, however, given the broad nature of the storm
and lack of inner-core organization, these winds may not be mixing
down as efficiently as usual.  The initial intensity remains at 75
kt for this advisory.

Ernesto is moving to the north at about 12 kt.  The model guidance
is tightly clustered and shows the hurricane turning to the
northeast within a day or so while moving through a break in the
subtropical ridge towards a trough located off the coast of the
eastern United States.  As the trough lifts by the weekend, Ernesto
should slow and turn to the north-northeast or north, while
approaching Bermuda on Friday night and Saturday.  By the end of
the weekend, Ernesto is expected to accelerate northeastward near
the coast of Atlantic Canada.  There have been little changes
to the most recent NHC track forecast, which lies just west of the
corrected consensus aid, HCCA.

Model guidance is still suggesting that some continued gradual
strengthening is possible in the next day or so.  The deep-layer
vertical wind shear is forecast to be weak to moderate, and Ernesto
should be over warm waters for the next few days.  However, the
broad nature of the current circulation, coupled with some dry air
ingestion, will likely slow the intensification rate.  Ernesto is
now forecast to peak at 95 kt in 24 h, which is near the top of the
model guidance envelope.  Beyond a day, the shear is expected to
increase and induce gradually weakening, though the warm waters and
positive interaction with the upper-level trough will likely allow
Ernesto remain a powerful hurricane as it moves north of Bermuda.


Key Messages:

1. Ernesto is expected to approach Bermuda late Friday and be near
the island Saturday and Saturday night.  A prolonged period of
strong winds and storm surge is expected on Bermuda beginning late
Friday, and a hurricane warning is in effect for the island.
Preparations to protect life and property should be rushed to
completion.

2. Rainfall associated with Ernesto is expected to begin to affect
Bermuda later today and may result in flash flooding Friday through
this weekend.

3. Even though Ernesto is forecast to remain well offshore the U.S. 
East Coast, swells generated by the storm are expected to reach the 
area during the next few days, including over the weekend.  Beach 
goers should be aware of a significant risk of life-threatening surf 
and rip currents, and stay out of the water if advised by 
lifeguards.  Surf and rip currents are also possible on the 
Dominican Republic, the Turks and Caicos, the Bahamas, and Bermuda 
during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT  15/1500Z 25.0N  69.2W   75 KT  85 MPH
12H  16/0000Z 26.6N  68.7W   85 KT 100 MPH
24H  16/1200Z 28.5N  67.5W   95 KT 110 MPH
36H  17/0000Z 30.3N  66.3W   90 KT 105 MPH
48H  17/1200Z 32.0N  65.5W   85 KT 100 MPH
60H  18/0000Z 33.6N  65.1W   80 KT  90 MPH
72H  18/1200Z 35.6N  64.6W   80 KT  90 MPH
96H  19/1200Z 41.6N  60.5W   80 KT  90 MPH
120H  20/1200Z 48.6N  48.1W   60 KT  70 MPH...POST-TROP/EXTRATROP

$$
Forecaster Bucci/Onderlinde